Pre-potting means to take a 25 second stat increase potion, before the pull of a boss fight.
Why - Because you can only use one buff increasing potion per battle. However, if you use a potion 2 seconds before the tank pulls, you will start the battle with increased stats for 23 seconds and then be able to use another potion 46 seconds later. So… two potions ...per battle are better than one.
Does it make a difference?
Let’s say Brackenspore has 50 million health. The average raiding is doing 16k per second, but with the 23 extra second at the start does 30k. for a dps team of 11 all pre-potting that is 14k extra dps per raider per second (14,000 x 11 x 23 secs = 3.5 million) 7% of the bosses health.
How many wipes, under 10% health, could have been avoided if everyone had pre-potted.